At a glance
Effects
- Slows hair loss / regrowth: Improves hair count and growth in male-pattern hair loss over months; benefit reverses within ~12 months of stopping.[2][3]
- Shrinks the prostate: Reduces prostate volume by about 20% and improves urinary flow in BPH, and may delay the need for surgery.[5][8]
- Lowers DHT: Reduces serum DHT by roughly 65–70% at 1 mg/day; serum testosterone rises modestly but usually stays within normal range.[6][9]
- Lowers PSA: Roughly halves prostate-specific antigen (PSA) readings, so PSA results must be interpreted against an adjusted baseline.[9]
5-alpha-reductase inhibitor (antiandrogen)
Oral tablet (1 mg hair loss, 5 mg BPH)
~5–6 hours (up to 8 in men >70)
Hair: assess at 12 months
Contraindicated; teratogenic in pregnancy
About Finasteride
Every point here is drawn from public medical and harm-reduction sources. A bracketed number after a claim — like [1]— is a reference: tap it to open the exact source it's based on (numbered list at the bottom). It is not a rating or score. Educational information, not medical advice.
Product specifics
- Est. delivery
- 3–7 business days · EU tracked
Product details as stated by the vendor (claims, not independently verified). Delivery is our standard EU estimate.
What it is
How it works
Finasteride blocks the enzyme 5-alpha-reductase (mainly the Type II isoenzyme), which normally converts testosterone into the more potent androgen dihydrotestosterone (DHT).[1][4] DHT drives both prostate enlargement and the follicle miniaturisation behind male-pattern baldness, so lowering it shrinks the prostate and slows hair loss.[2][5] At 1 mg/day it cuts circulating DHT by roughly 65–70% and scalp/prostate DHT by up to 80–90%.[6] The effect outlasts the drug's short blood half-life because finasteride binds tightly to the enzyme, which itself turns over slowly (about a 30-day half-life for the Type II complex).[4][8]
Risks & side effects
Most important: A subset of users develop sexual dysfunction — reduced libido, erectile dysfunction and ejaculation problems — and in some men these effects, along with depression and suicidal ideation, have been reported to persist after stopping the drug.[7][8] Because finasteride is often taken for a cosmetic, non-life-threatening reason, weigh these neuropsychiatric and sexual risks carefully before starting.[10]
Common
Serious
- Depression, mood changes and suicidal ideation (FDA-labelled)[7][8]
- Sexual dysfunction that persists after discontinuation in some men ('post-finasteride' reports)[7][8]
- Male infertility / poor semen quality (often improves after stopping)[7]
- Teratogenic — can cause abnormal genital development in a male fetus; women who are or may be pregnant must not handle crushed/broken tablets[12]
Safety & harm reduction
- PSA testing in older men — finasteride roughly halves PSA, so interpret against an adjusted (~halved) baseline; a failure to drop PSA by ~50%, or a rising PSA on treatment, warrants prostate cancer evaluation[9][13]
- Watch for and report mood changes, depression or suicidal thoughts[7][8]
- Report persistent sexual side effects to a clinician[7]
- Disclose finasteride use before any PSA/prostate-cancer screening so results are interpreted against a halved baseline[9]
- If neuropsychiatric or sexual symptoms appear, discuss stopping with a clinician — do not stop abruptly without advice in BPH[3]
- Pregnant partners should avoid contact with crushed/broken tablets and with semen per labelling precautions[12]
Dosage context
Commonly-reported, not a prescription: clinical dosing is 1 mg/day for male-pattern hair loss and 5 mg/day for BPH.[5][9] Dose-ranging data show doses below 0.5 mg/day produce little DHT suppression while doses above 5 mg/day add little extra benefit.[11] Hair-loss treatment is typically continued for at least 12 months before judging efficacy, and benefit reverses if stopped.[3][9] Any use should be supervised by a clinician.
Sources
- 1.DrugBank — Finasteride
- 2.Medical News Today — Finasteride oral tablet
- 3.MedlinePlus — Finasteride
- 4.NCBI PMC — Finasteride and 5α-reductase isoenzymes
- 5.Drugs.com — Finasteride uses
- 6.Wikipedia — Finasteride (pharmacology)
- 7.Drugs.com — Finasteride prescribing information
- 8.StatPearls (NCBI) — Finasteride
- 9.DrugBank — Clinical pharmacokinetics of finasteride
- 10.Psychiatry Redefined — finasteride mood/neurosteroid review
- 11.PubMed — Clinical pharmacokinetics/pharmacodynamics of finasteride
- 12.MedCentral — Finasteride monograph
- 13.FDA label — PROPECIA (finasteride) 2022
- 14.FDA/DrugBank — finasteride interactions (label)
- 15.ClinicalTrials.gov — finasteride hepatic metabolism (CYP3A4)
This information is provided for educational and harm-reduction purposes only. It is not medical advice. These substances can carry serious health risks; effects and safe use vary by individual. Consult a qualified healthcare professional before use. Legal status varies by country — it is your responsibility to know your local law. We do not encourage misuse.